Enhanced petroleum-based aliphatic hydrocarbon lubricant using inorganic fullerence-like nano-spheres

ABSTRACT

The present invention provides a new composite lubricant to deliver lubrication effectiveness by reducing friction coefficient and wear rates and increasing the load bearing capacity, said composite lubricant comprising a base of time-proven aliphatic hydrocarbon into and dispersed throughout which are both nested, hollow, fullerene-like nano-spheres and petroleum distillates previously used as antistatic additives to increase conductivity of the composite lubricant.

BACKGROUND OF THE INVENTION

Petroleum Aliphatic Hydrocarbons:

Crude oil contains aliphatic hydrocarbons composed of nothing but hydrogen and carbon. The carbon atoms link together in chains of different lengths. Different substances come from combinations whose only difference is the length of the carbon chains. Since different chain lengths have progressively higher boiling points, they can be separated out by distillation. In an oil refinery crude oil is heated and the different chains are distilled off by their vaporization temperatures. The lightest four chains are all gases at room temperature. The chains up through C₁₈H₃₂ or so are all liquids at room temperature, and the chains above C₁₉ are all solids at room temperature.

The chains in the C₅ to C₇ range are all very light, easily vaporized, clear liquids called naphthas. They are used as solvents in dry cleaning fluids, paint solvents and other quick-drying products. The chains from C₇H₁₆ through C₁₁H₂₄ are blended together and used for gasoline. Next is kerosene, in the C₁₂ to C₁₅ range, followed by diesel fuel and heavier fuel oils like the heating oil for houses, followed by the lubricating oils. These oils no longer vaporize in any way at normal temperatures. For example, engine oil can run all day at 250 degrees F. (121° C.) without vaporizing at all. Oils go from very light (like 3-in-1 oil) through various thicknesses of motor oil through very thick gear oils and then semi-solid greases. Finally, chains above the C₂₀ range form solids, starting with paraffin wax, then tar and finally asphaltic bitumen.

The following are the 15-to-20-carbon, straight chain length, n-alkanes derived from petroleum by distillation that are used as lubricants. CAR- FORMULA BON NAME (MOL WT.) M.P. B.P CAS RN C(15) n-Pentadecane C₁₅H₃₂ (212.42) 10 C. 271 C. 629-62-9 C(16) n-Hexadecane C₁₆H₃₄ (226.44) 18 C. 287 C. 544-76-3 C(17) n-Heptadecane C₁₇H₃₆ (240.47) 22 C. 302 C. 629-78-7 C(18) n-Octadecane C₁₈H₃₈ (254.50) 28 C. 316 C. 593-45-3 C(19) n-Nonadecane C₁₉H₄₀ (268.53) 32 C. 329 C. 629-92-5 C(20) n-Eicosane C₂₀H₄₂ (282.55) 37 C. 343 C. 112-95-8

Addition of phosphates and sulfur improve the lubrication ability of petroleum derivatives, where the base hydrocarbon lubricant also functions as a carrier of metallic salts. Today, numerous chemicals are added to provide functionality to the base hydrocarbon lubricant. Aliphatic hydrocarbon lubricants with various additives have found use in many applications.

Additive to Increase Conductivity of Hydrocarbons:

Static electric charge can build up in hydrocarbon liquids that get internally agitated during transfer operations such as discharging from a hose or nozzle, moving through pipes, mixing, pouring, agitation, and splashing. This static electric charge can get carried downstream, and the potential for accidents can increase with this increase in built-up static charge. This build-up of charge is more pronounced with low-conductivity hydrocarbons (naptha, gasoline and blends).

Low conductivity hydrocarbons are defined as below 50 pico-siemens per meter conductivity. A class of products called “antistatic fluids” or “antistatic additives”, which also are petroleum distillates, are added to raise the conductivity of these low conductivity hydrocarbons to a safer level at or above 100 pico-siemens per meter conductivity. Very small quantities of these antistatic fluids are required to raise the conductivity to the desired levels: some 10 to 30 milliliters per 1,000 gallons of hydrocarbon.

Typical antistatic fluids are ExxonMobil™ Chemical's line of de-aromatized hydrocarbon fluids known as Exxsol™ fluids. Representative fluids and their distillation points are shown below. The IBP is the temperature at which 1% of the material is distilled and the DP is the temperature at which 96% of the material is distilled. Exxsol ™ Antistatic Fluids Distillation Hexane D 40 D-3135 D 60 IBP, (° C.) min. 65 150 152 177 DP, (° C.) max. 71 210 182 220 Additive (ml/1000 gallons) 30 30 10 30

Fullerene-Like (IF) Nano-Spheres:.

The terms ‘nano’ and ‘nested, hollow, fullerene-like nano-spheres’, used to describe the structure of a class of inorganic compounds, have their derivation from a combination of the Greek language and science fiction literature. The word nano comes from the Greek word ‘nanos’ (vavoo) for dwarf, arid refers to structures that are about one billionth of a meter in size, or a thousand times smaller than the diameter of a human hair. The nested structure of hollow, fullerene-like nano-spheres is analogous to that of an onion or a Russian doll, where inside all but the innermost shell there exists a slightly smaller shell, and within that slightly smaller shell exists another slightly, slightly smaller shell, recursing to the innermost shell. These structures are called ‘fullerene-like’ because each shell resembles the geodesic dome design of Buckminster Fuller.

Layered inorganic compounds of the type MX₂ (where M is molybdenum, tungsten or niobium, and X is sulphur or selenium) are known lubricants in large flat platelets, with weak interlayer bonding which facilitates transfer of the materials to the upper and lower mating surface. The transfer is responsible in part for low friction and wear. These large flat platelets have, however, the drawback of having reactive edges.

Nested, hollow, fullerene-like nano-spheres made from layered inorganic compounds of the type MX₂ have no exposed reactive edges, but retain as their inner and outer mating surfaces the lubrication properties of the large flat platelets. The small size, shape, composition and structure of these nano-spheres make them superior lubricants. Nested, hollow, fullerene-like nano-spheres can be made from inorganic compounds including tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂).

Nested, hollow, fullerene-like nano-spheres of tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂) have demonstrably a superior form factor for lubrication than the platelet forms of the same materials, lacking the weakness of the reactive edges. However, such nested, hollow fullerene-like nano-spheres, because of their small size, may rotate at high speeds and generate static electricity, requiring further means to avoid reduction in performance associated with local breakdown of hydrocarbons or safety problems.

SUMMARY OF THE INVENTION

In the present invention, an aliphatic hydrocarbon lubricant base has both a quantity of nested, hollow, fullerene-like nanospheres made of the named inorganic compounds added to, dispersed through, and suspended in it, and a quantity of petroleum distillate previously used as an antistatic additive added in order to increase the conductivity of the composite lubricant so as to provide a conduit to an electric ground, thereby both avoiding reduction in performance associated with local breakdown of the hydrocarbon and safety problems caused by static build-up.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a nested, hollow, fullerene-like nano-sphere [1] with three layers [1A, 1B, and 1C], with the top-right quadrant cut away to show the nesting of the nano-sphere's layers.

FIG. 2 is a representation of the composite lubricant between a first metal surface [5] and a second [7], wherein the aliphatic hydrocarbon base [11] has dispersed throughout it both hollow, fullerene-like nano-spheres made of the inorganic compounds [13 a, 13 b, 13 c, 13 d, 13 e, 13 f, 13 g, 13 h, 13 i, 13 j] and an anti-static additive [15], the latter allowing any static charge from the movement or rotation of the hollow, fullerene-like nano-spheres made of the inorganic compounds to be safely grounded.

DETAILED DESCRIPTION OF THE INVENTION

It is the objective of the invention to provide a new, composite lubricant reducing its friction coefficient and wear rates and increasing its load-bearing capacity, by taking advantage of the respective, particular, and complementary capabilities of its differing incorporated materials

An aliphatic hydrocarbon lubricant base is modified by adding an anti-static additive and a quantity of nested, hollow, fullerene-like nano-spheres made from the set of inorganic compounds tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂), wherein the aliphatic hydrocarbon lubricant base serves as a matrix support for the nano-spheres, and the nano-spheres act as nano-ball bearings and thereby reduce friction to levels comparable with those found in ball bearings, while the anti-static additive enables any static charge created by the spinning of the nano-spheres to be grounded through the composite lubricant.

The nested, hollow fullerene-like nano-spheres are made from the set of inorganic compounds tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂), and have a diameter between 8 and 240 nm, with a higher limit of 200 nm being better and preferentially between 10 and 70 nm. These nested, hollow fullerene-like nano-spheres are preferentially present in the composite lubricant in a quantity of between 0.1% and 7.5% by weight

In view of their small size these nano-spheres may rotate at high speeds and generate static electricity, especially when the composite lubricant is in use. To reduce that hazard a conductive anti-static additive is also added to and distributed throughout the aliphatic hydrocarbon lubricant base in which these nano-spheres are suspended. This composite lubricant will thereby avoid reduction in its performance associated with local breakdown of the aliphatic hydrocarbon base and safety problems from static-electric build-up.

The quantity of antistatic additive required to increase the conductivity of the aliphatic hydrocarbon lubricant base is determined by measuring the conductivity of the composite lubricant as the antistatic additive is mixed in and stopping when the desired conductivity consistent with the application is reached, after which the blended aliphatic hydrocarbon base and antistatic additive mixture has the nested, hollow fullerene-like nano-spheres also blended in, to obtain the final composite lubricant. The amount of antistatic additive mixed in will range between 0.001% and 10% of the aliphatic hydrocarbon lubricant base by weight, and preferentially between 1% and 7.5% by weight, though it may be mixed in at a liquid volume of between 10 and 100,000 parts per million.

According to another feature of the invention the chain length of the aliphatic hydrocarbon lubricant base is selected from those with between 15 and 20 carbons, with the selection being guided by the consideration of which chain length is most consistent with the composite lubrication's use and the need for the aliphatic hydrocarbon lubricant base to provide a sufficient support matrix in which the nested, hollow, fullerene-like nano-spheres are dispersed throughout the aliphatic hydrocarbon lubricant base and will maintain said dispersion under expected operating conditions.

According to still another feature of the invention the antistatic additive is selected from a population of commercially available materials based on the ability of the material's chemical compatibility with the aliphatic hydrocarbon lubricant base and the cost effectiveness of raising the conductivity of the composite lubricant to the desired level for the composite lubrication's anticipated application. 

1. A new composite lubricant to deliver lubrication effectiveness by reducing friction coefficient and wear rates and for increasing the load bearing capacity, said composite lubricant comprising: an aliphatic hydrocarbon lubricant base; a quantity of nested, hollow, fullerene-like nano-spheres made from at least one layered inorganic compound from the set of tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂); and, a petroleum distillate from the class of those previously used as an antistatic additive; whereby the aliphatic hydrocarbon lubricant base serves as a matrix support for the hollow, fullerene-like nano-spheres, the nested, hollow, fullerene-like nano-spheres act as nano-ball-bearings and thereby reduce friction to levels comparable with those found in ball bearings, and the petroleum distillate from the class of those previously used as an antistatic additive increases the conductivity of the aliphatic hydrocarbon lubricant base.
 2. A composite lubricant as set forth in claim 1 wherein the aliphatic hydrocarbon lubricant base is selected from a the set of aliphatic hydrocarbon lubricants having from 15-to-20-carbon straight chain length n-alkanes derived from petroleum by distillation, said set including n-Pentadecane, n-Hexadecane, n-Heptadecane, n-Octadecane, n-Nonadecane and n-Eicosane.
 3. A composite lubricant as set forth in claim 2 wherein the nested, hollow, fullerene-like nano-spheres made from at least one layered inorganic compound from the set of tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂): are between 8 nm and 240 nm in diameter; and, are present in a quantity of between 0.001% and 20% by weight in the composite lubricant.
 4. A composite lubricant as set forth in claim 3 wherein the nested, hollow, fullerene-like nano-spheres made from at least one layered inorganic compound from the set of tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂) are between 10 nm and 200 nm in diameter.
 5. A composite lubricant as set forth in claim 3 wherein the nested, hollow, fullerene-like nano-spheres made from at least one layered inorganic compound from the set of tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂) are between 10 nm and 70 nm in diameter.
 6. A composite lubricant as set forth in claim 3 wherein the nested, hollow, fullerene-like nano-spheres made from at least one layered inorganic compound from the set of tungsten disulfide and selenium (WS₂, WSe₂), molybdenum disulfide and selenium (MoS₂, MoSe₂), and niobium disulfide and selenium (NbS₂, NbSe₂) are present in the composite lubricant in a quantity of between 0.1% and 7.5% by weight.
 7. A composite lubricant as set forth in claim 3 wherein the petroleum distillate from the class of those previously used as an antistatic additive is selected from a population of commercially available antistatic additive materials based on the chemical compatibility of the particular antistatic additive material selected with the aliphatic hydrocarbon lubricant base and the cost effectiveness of raising the conductivity of the composite lubricant to the desired level for the lubrication application, said class specifically including Exxsol™ Antistatic Fluids D 40, D-3135, D 60 and Hexane.
 8. A composite lubricant as set forth in claim 3 wherein the quantity of petroleum distillate from the class of those previously used as an antistatic additive is determined by measuring the conductivity of the composite lubricant as the petroleum distillate is added and stopping when the attained conductivity of the composite lubricant matches that desired conductivity consistent with the anticipated application, after which the nested, hollow, fullerene-like nano-spheres are added to and blended with the combined aliphatic hydrocarbon base and petroleum distillate mixture to obtain the final composite lubricant.
 9. A composite lubricant as set forth in claim 3 wherein the quantity of petroleum distillate from the class of those previously used as an antistatic additive mixed in ranges between 0.001 and 10% of the aliphatic hydrocarbon lubricant base by weight.
 10. A composite lubricant as set forth in claim 3 wherein the conductivity of the aliphatic hydrocarbon lubricant base is increased by adding sufficient quantity of the petroleum distillate from the class of those previously used as an antistatic additive to increase the conductivity of the mixture to that level which will allow the static electricity generated by any high speed rotation of the nested, hollow, fullerene-like nano-spheres, suspended in the composite lubricant, to ground safely under the worst conditions of use anticipated and thereby prevent any reduction in performance associated with local breakdown of the hydrocarbon or safety problems.
 11. A composite lubricant as set forth in claim 3 wherein the quantity of petroleum distillate from the class of those previously used as an antistatic additive mixed in ranges between 10 and 100,000 parts per million by liquid volume. 